1. Field of the Invention
This invention relates to metal-ceramic composite bodies and a method of producing the same, and more particularly to a metal-ceramic composite body obtained by joining a metallic member to a ceramic member through interference fitting and a method of producing the same.
2. Related Art Statement
Ceramics such as zirconia, silicon nitride, silicon carbide and so on are excellent in the mechanical strength, thermal resistance and abrasion resistance, so that they are noticed to be used as high-temperature structural materials or abrasion-resistant materials for engine parts, gas turbine engine parts and the like. However, the ceramics are generally hard and brittle, so that they are poor in the formability as compared with metallic materials. Furthermore, they are poor in the toughness and weak in the resistance to impact force. Therefore, it is difficult to make machinery components such as engine parts and the like from only the ceramic materials, so that it is usually used as a composite body of metallic member and ceramic member.
Heretofore, in the manufacture of products such as turbocharger rotor and the like by joining metal and ceramic to each other, when the ceramic member is integrally united with the metallic member by inserting the protrusion formed in the ceramic member into the depression or through-hole formed in the metallic member. For example, both the members are heated at a certain temperature and joined to each other and then cooled, whereby they are joined to each other based on the fastening force between the metallic member and the ceramic member produced by the difference in thermal expansion therebetween.
The metallic member and the ceramic member have hitherto experimentally been joined to each other by heating at an approximately service temperature or at a temperature equal to or somewhat higher than the service temperature. That is, the heating temperature has hitherto been set only by considering the interference in the cooling, and the restriction of the heating temperature has not been made at all.
Lately, it is highly demanded to use the metal-ceramic composite body at higher temperature, while it is strongly required to make the interference large so as to provide a strong fastening force. Therefore, if it is intended to join the metallic member to the ceramic member through interference fitting by heating to higher temperature, there may be caused a case that the joining strength is not obtained in accordance with the material used, i.e. a composite body having no joining force between metal and ceramic may be produced.